Study on stress corrosion behavior and mechanism of X70 pipeline steel with the combined action of sulfate-reducing bacteria and constant load

The stress corrosion behavior of X70 pipeline steel with the combined action of SRB and constant load was investigated by constant load experiments and electrochemical testing. The results showed that plastic stress and SRB significantly increased the SCC susceptibility of X70 pipeline steel. SRB promoted the occurrence of pitting corrosion, and there was a synergistic effect of SRB and plastic stress together in promoting the pitting on pipeline steel. The elastic stress was not significant in promoting corrosion. The synergistic effect of tensile stress and SRB was explicated from the perspective of corrosion thermodynamics.

Automated summary

The stress corrosion behavior of X70 pipeline steel under the combined action of SRB and constant load was investigated. It was found that plastic stress and SRB greatly increased the susceptibility of X70 pipeline steel to stress corrosion cracking (SCC). SRB promoted pitting corrosion, and the synergistic effect of SRB and plastic stress further enhanced the occurrence of pitting on the pipeline steel. Elastic stress did not play a significant role in promoting corrosion. The synergistic effect of tensile stress and SRB was explained from the perspective of corrosion thermodynamics.